How to Get Rid of Botrytis Cinerea in Basil

Save your basil plants with prompt pruning.

Botrytis cinerea, also known as gray mold, is a common basil disease. It often attacks during extended periods of cool, wet weather. Each time basil is harvested under these conditions, the fungus enters through the pruning wounds. When Botrytis cinerea first strikes, it shows up as white, moldy patches. Eventually it turns dark gray and develops black structures. The best chance you have of combating Botrytis cinerea is to attack it early. Once the fungus reaches the base of the plant, it is too late to save it.

Things You'll Need

• Rubbing alcohol
• Pruning shears

Instructions

1. Wipe your pruning shears' blades down with rubbing alcohol before you make your first prune. Also wipe them down after each pruning cut. This will prevent accidental fungal transfer between plants and leaves.

2. Prune all infected plant material. Infected basil tissue contains white or gray mold. Stems develop a red or brown cover, and become stiff and woody. Prune all infected leaves at their base. Prune infected stems back to the nearest fork in the stem, at least 1 inch into healthy tissue. If the infected tissue is near the base of the plant, prune the stem all the way to soil level.

3. Remove all infected plant tissue, mulch and other plant debris from the base of the plant. Botrytis cinerea actively feeds on dead plant tissue in garden beds and easily spreads to living plant tissue.

Tips & Warnings

• If your basil is growing indoors or in a greenhouse, clean with soapy water all hard surfaces (walls, windows, tables pots) near the basil to remove any nearby fungal spores.

• Botrytis cinerea often enters home garden through new plants and seeds. Make sure that any basil seed you purchase is certified disease free. Quarantine new plants for two weeks before introducing them to your garden.

• Wait until periods of sunny, dry weather to prune. Ideally, the weather should remain sunny and dry for 24 to 48 hours after harvest.

References

• Horticultural Development Company: Grey Mould
• Clemson Cooperative Extension; Basil; Joey Williamson; December 2008